This cross-sectional study used the same instrument to examine nutrition in community-dwelling patients with different mental illnesses from Palestine and Western countries. Compared to the normative group, the Palestinian sample consumed more diet products, more traditional foods and consumed unhealthy snacks more frequently. A different set of eating behaviours were reported by the Western clinical sample, including fewer healthy food and drinks, fewer traditional products and more frequent eating due to negative emotions. Between the Palestinian and Western clinical samples, the Palestinian sample reported statistically significantly more frequent consumption of traditional foods and more frequent unhealthy snacking. Finally, these differences in eating behaviours were also associated with obesity across locations. In Palestine, more frequent unhealthy snacking was associated with a greater risk of being overweight or obese. In contrast, for Western patients with mental illness, a greater consumption of diet products and eating due to negative emotions were associated with obesity.
Unexpectedly, the Palestinian sample exceeded rates of obesity compared to the Western sample. For the Palestinian group, 40% of patients were overweight and 22% were obese, while the corresponding rates were 32% and 15% in the Western sample. This is in contrast to previous research which found that obesity in Middle Eastern nations should be approaching Western levels due to increasing urbanisation, changes in the availability and energy-content of food and reductions in physical activity [16, 17]. Simultaneously, the results also indicate more frequent consumption of traditional foods and unhealthy snacking in the Palestinian group than the Western normative or clinical groups, which may be associated with the increased prevalence of obesity. In contrast, the Western clinical group consistently indicated less frequent consumption of healthy food and drink as well as greater eating due to negative emotions than the normative group. These differences in dietary composition indicate that Western-based studies examining nutritional composition of patients with SMI cannot directly be generalised to other non-Western countries.
The Western patients classified as obese had a 2.54 OR for consuming low-fat products and a 0.29 OR for eating traditional products (such as sausages, eggs, chocolate and cake which are typically high in fat). These results are inconsistent with previous literature which has found that people with SMI consume more high-fat meals  and less low-fat food types  than normative groups. This discrepancy in results may reflect obese patients actively working to consume a low-fat diet given the well known association between obesity and poor health outcomes. Unlike patients classified as obese, overweight patients ORs were only approaching statistical significance for both food types (p = .088 and .072, respectively). Consequently it is suggested that greater emphasis on interventions and encouragement to consume lower-fat products should be extended to patients in the overweight BMI range. Of further interest is the finding that Western patients who were obese reported a 1.85 OR of eating due to negative emotions and that this effect was not statistically significant for the Western overweight group or any Palestinian BMI group. Eating as an emotional regulation strategy is an extensive avenue of research  and may be a differentiating factor between overweight and obese patients with SMI. The results of this study suggest that in Western patients with SMI, nutritional interventions which specifically target eating due to negative emotions would be beneficial in reducing obesity in this population. However, this effect is location-specific and may not be relevant for Palestinian patients with SMI.
For the Palestinian sample the eating behaviours which contributed to being overweight and obese differed from the Western sample. Frequent snacking on unhealthy food items, such as eating potato crisps between meals, was the primary substantial risk factor for both being overweight and obese. Furthermore, low consumption of diet products and eating alone were also associated with an increased risk of being overweight. Thus in Palestinian patients with SMI, reducing frequent unhealthy eating would be an effective broad strategy to reduce BMI across weight categories.
There are some limitations with the present study that can be addressed by future research. Although patients were treated with medication appropriate to their disorder, thus making this study ecologically valid, specific types of medication were not taken into account. It has been demonstrated that certain medications are associated with changes in eating habits and body weight [21–23] and so future studies are encouraged to take into account medication types to better understand the proportion of variance medication contributes to differences in eating habits and weight. A second limitation is that the Palestinian and Western samples vary in demographic and diagnostic categories and so comparisons with the German normative group require some caution in attributing the differences in eating behaviours due to location alone. Nevertheless, demographic factors and diagnostic criteria are controlled for in logistic analyses; however the relatively low sample size in the underweight category limits the conclusions which can be made for this weight category. Further limiting conclusions is that a time lag is noted between the time of the normative data (published in 1995) and the data of the study (collected between 2001 and 2008). During this time BMI and negative eating habits have shown an upward trend , and so earlier results may underestimate the present association between mental illness, obesity, and eating habits. Furthermore, normative information is not available from Palestine, and thus regional differences in diet may be responsible for the observed differences in nutritional behaviours for people with SMI. Nevertheless, this does not detract from the conclusion that regional differences in patients with SMI should be taken into account when undertaking weight management interventions. Lastly, this study focused on only one Middle Eastern country (Palestine) and so the results are limited in their generalisability to other Middle Eastern populations.